I am trying to issue a UA Award using my AI miles on the route LAS-EWR-DTW. AI reps are telling me it is impossible to issue this on a single PNR. They are trying to issue 2 tickets for LAS-EWR and EWR-DTW separately. Since my itinerary only has a layover of ~1 hour I was wondering if there is a way to merge the PNRs so as to enable me to check bags through to DTW and also be protected in case of IRROPS. AI is unable to give me any answer regarding this. According to them United is not letting them issue this ticket as this is considered backtracking.